Automatic safety device for fluid-compressors.



PATENTED JULY 24, 1906.

2 SHEETS-SHEET 1.

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J. W. DAWSON. AUTOMATIC SAFETY DEVICE POR FLUID GOMPRESSORS.

APPLICATION FILED DEO. 31, 1904.`

PATEN'IED JULY 24, 1906A.

` J. W. DAWSON.

AUTOMATIC SAFETY DEVICE FUR FLUID COMPRESSORS. APPLIGATION FILED DBO. 31, 1904.

2 BHEBTS-SHEET 2.

Lcna s es p formed by said plate.

, ITED STATES PATENT orrien.

JAMES W. DAWSON, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF TWO-TWELFTHS TO GEORGE BEAGLEY, OF SAN FRANCISCO, CALI- FORNIA.

AUTOMATIC SAFETY DEVICE FOR FLUID-COMPRESSURS.

i Specification of Letters Patent.

Patented .i my 24, ieee.

To all whom it may concern.-

Be it known that I, JAMES W. DAWSON, a citizen of the United States, residing in the city and county of San Francisco and State of California, lhave invented certain new and useful Improvements in Automatic Safety Devices for Fluid-Compressors, of which the following is a specification.

This invention relates t a safety device for use in connection with compressors and particularly to automatic` safety devices used with gas-compressors operated forany purpose whatsoever and driven by any suitable power.

The object of this invention is the production of a safety device of this sort that will be easy of'operation, accurate, and durable.

To this end the device embodying the invention is by suitable mechanism connected to the receptacle containing the fluid under compression and is so constructed that upon an excess of pressure in said receptacle it will act upon an electric circuit through Whose agency the motive power driving the compressor is controlled. v y

The invention therefore consists in an automatic safety device for compressors substantially as hereinafter described and claimed.

In the accompanying drawings, which form a part of this specification, Figure 1 represents the safety device in elevation; and Fig. 2 represents a section thereof, taken in the plane indicated by the line A B in Fig. 1.

The several parts of the automatic safety device are preferably mounted together upon a backboard, foundation, or base, by means of which it may be secured in place Wherever most convenient. These parts comprise the fluid-pressure chamber 8, the cylinder 6, its

iston, the catch-lever 21, and the electric 'fe-switch 1.

The fluid-pressure chamber consists of a cavity in the middle of the base 5, which cavity is covered by the plate 7, which forms one wall thereof. This plate is preferably corrugated, as at 11, and in the surfaces of the lateral walls of the cavity 8 contiguous to said plate is formed a channel corresponding to the corrugation of said plate, and the inner edges of these walls are sloped toward the cavity, thereby extending the area of the wall The cylinder 6 is flanged at its base, and between this fiange and the base 5 vthe edge of the plate 7 is firmly secured, being hermetically sealed to the base 5 by means of the gasket 10. The piston in cylinder 6 consists of the head ,15 and the rod 16. Said head is of such extent as to cover the entire area of the plate-wall of thel cavity 8 and preferably extends over the corrugated surface of said plate, thereby reaching beyond the edge 12 of the lateral walls of chamber 8. By this construction said walls normally support the piston and relieve the flexible wall or diaphragm from thepressure of the piston when the iiuid in the chamber is under normal tension.

Upon the piston-rod is movably located a collar 20, between which and the piston-head is confined a spiral spring 18, which resists the pressure of the fluid in the chamber 8.

The tension of this spring may be varied by I means of an exteriorly-screw-threaded sleeve 17, seated in the outer end of cylinder 6 and forming an abutment for said collar. The outer end of the sleeve is preferably squared for the application thereto of a wrench by which to turn it in adjusting the tension of spring 18.

To the side of cylinder 6 a catch-lever 21 is pivoted-as, for instance, by means of the bracket 22, attai'fhcd to or formed integral with said cylinder. Through the outer end of the catch-levexI there is passed a screw 23, which engages the outer end of the, pistonrod, and to the bracket 22 is secureda platespring 24, which presses upon the other end of the lever 21. This spring-pressed end of the lever 21 is preferably notched, as at 25, for engagement with the movable part of the electric switch 1. This switch may be of any desired form, but by reference a double-pole knife-switch is use( AT he handle of this switch is indicated at 3 and has let into it a plate, as 26, to take the wear incident to the engagement of the catch-lever with said handle. A looped spiral spring 27 is secured to the backboard and engages by the middle of its loop with the rear side of the switch-handle, so that when said handle is released from the catch the switch will be immediately thrown open by this spring. The electric conductors leading to and from the switch are indicated at 2, and the buffer for the' switch when thrown open is indicated at 4.

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To the fluid-pressurechamber 'is connected a pressure-gage, Y as indicated at 14. The connection .of said chamberfwiththecompresser or the reservoir of compressed fluid is indicated at 13.

By the proper adjustment. of thetension vof spring 18 by means of the sleeve 17 and the swin of catch-lever 21 by means of the screw 23 t e switch 1 may be operated to stop further compression of the fluid at any`de- ,.f sired degree of compression indicated by the pressure-ga0e-14. Obviously the switch -1 may contro v anv electric motor used 1in driving the com ressor, on it may control an elec'- tric device or disconnecting the compressor fromanyothersort of motor.- 1 4 Changes in theform, construction, and location of the several partsembodyin-gmyinvention may bemade without departing from the spirit thereof-f The invention claimed is 1 l. In an automatic safety device forcompressors, the combination cfa-chamber for reception of fluid .under pressure,- a springpressed piston movable by. the pressure'in said chamber, a cylinder in which said pistonA and spring are confined-,.- acatch-lever pivoted to said cylinder, amadjusting-screw interposed between said lever and the rod of the piston, an electric `switch, a s ring for throwing the movable lmember of t e-switch, a handle on said switch with which said catchengages 'to hold the switch against the action of the spring, and a spring forholding theicatchlever in engagement with said handle and with thepiston-rod.. 1 1 'i 2,. An automaticv safety device for `compressors, consisting of a back or foundatioma combined luidfpressure chamber-and cylinder mounted thereon, a springressed piston within the cylinder and movab e by=the1presi sure in said chamber, a gage connectedl to said chamber, an electric knife-switch mounted on 'said foundation, a spring-pressed .pivoted catch forl engaging .with .the handleof the swQitch and with the rod ofithe piston, and` a spiral looped spring attached to the foundation andpressing against said handle to throw the switch open when released fromthe catch by the movement of the piston.

.3; -An automatic. safety "'device for com pressors, consisting of a back ior`f`o'ndation, af combined iuid-pressure chamber and cylinder mounted thereon, one wall of which chamber is a corrugated plate and thelateral walls of which conform to the corrugations of said plate, a piston covering the entire area of said corrugated Wall, a devicel for applying to said piston a determinate pressure,v an electric switch mounted on said foundation, a'springressedpivotedc'atch for engafgxing witlitle handle of the sWitchard withl't ero'dof-'t'he piston; fand' Va spring 'attac'hed to the-foundationand ressmg againsttlre handle f" the 'switch to' t rowthe switchope'n when released from the catch by the movement of the pist0n. y l ..1 ,.IJ.'A.` ,.nl, l;A s

4. An automaticA 'safety' device forfco'r'npressors, consistingof aback 'or foundation, a combined fluid-pressure chamber 'a'r'idcylinder mounted thereon, va piston within' "the cylinder and movable by tV e pressure i'n' sail chamber, acllarmovableupon 'thefrd ofthe piston', Aa spring between 'the'piston`head and the collar, -an-externallythreaded 'sleeve' up on the rod andseated in'A the end ofthefc'ylinder and/forminganabutmentfor thesaid collar whereby-the desired tension may lbefgive'n to said springyan electric' switch mounted 'on said foundation, aspi-ing '-pressed pivoted catchV foren aging wit ofthe-switc and with the rod of`t'he piston, and a spring attached tothfoundation' and pressing against said movable member of the switch to-throW the switch openwhen' re'- leasedfrom the catch by the movement of the piston. f =Irr testimonywvhereof "I haveafxedmy signature; in presencevofsubscribing witnesses, this 18th day of Au stf1904x. i v JgAMES W. DAWSON. Witnesses: L 'f O. AfEeenRs, E. W. CURRIER the movableunemb'er 

